Definition of top-up:
(n) :
Additional credit purchased for a mobile phone.
(n) :
An addition.
(adj) :
That serves as an addition
(n) :
A serving of drink used to top up an existing glass.
(n) :
(insurance) An additional premium paid over the initial premium in order to increase benefit values.
(n) :
(medicine) A dose of epidural anesthetic added to previously injected spinal anesthetic in combined spinal-epidural anesthesia